const hellos = new Array(5).fill('hello') // [ 'hello', 'hello', 'hello', 'hello', 'hello' ]
const his = new Array(5).fill('hi', 2) // [ <2 empty items>, 'hi', 'hi', 'hi' ]
const byes = new Array(5).fill('bye', 1, 3) // [ <1 empty item>, '你好', '你好', <2 empty items> ]

console.log(hellos)
console.log(his)
console.log(byes)

// 覆盖
const arr = [1, 2, 3, 4, 5]
arr.fill(0)
console.log(arr) // [ 0, 0, 0, 0, 0 ]
